regmap: mmio: Fix MMIO accessors to avoid talking to IO port

Currently regmap MMIO is inconsistent with IO accessors. I.e.
the Big Endian counterparts are using ioreadXXbe() / iowriteXXbe()
which are not clean implementations of readXXbe().

That said, reimplement current Big Endian MMIO accessors by replacing
ioread()/iowrite() with respective read()/write() and swab() calls.

Note, there are no current in-kernel users that may utilize the
functionality of the IO ports on Big Endian hardware. All drivers
that use regmap MMIO either Little Endian, or they don't map IO
ports in a way that ioreadXX()/iowriteXX() may be utilized.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/20220808203401.35153-5-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap-mmio.c

@@ -104,7 +104,7 @@ static void regmap_mmio_write16be(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
 {
-	iowrite16be(val, ctx->regs + reg);
+	writew(swab16(val), ctx->regs + reg);
 }
 
 static void regmap_mmio_iowrite16be(struct regmap_mmio_context *ctx,
@@ -137,7 +137,7 @@ static void regmap_mmio_write32be(struct regmap_mmio_context *ctx,
 				  unsigned int reg,
 				  unsigned int val)
 {
-	iowrite32be(val, ctx->regs + reg);
+	writel(swab32(val), ctx->regs + reg);
 }
 
 static void regmap_mmio_iowrite32be(struct regmap_mmio_context *ctx,
@@ -204,7 +204,7 @@ static unsigned int regmap_mmio_ioread16le(struct regmap_mmio_context *ctx,
 static unsigned int regmap_mmio_read16be(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
 {
-	return ioread16be(ctx->regs + reg);
+	return swab16(readw(ctx->regs + reg));
 }
 
 static unsigned int regmap_mmio_ioread16be(struct regmap_mmio_context *ctx,
@@ -234,7 +234,7 @@ static unsigned int regmap_mmio_ioread32le(struct regmap_mmio_context *ctx,
 static unsigned int regmap_mmio_read32be(struct regmap_mmio_context *ctx,
 				         unsigned int reg)
 {
-	return ioread32be(ctx->regs + reg);
+	return swab32(readl(ctx->regs + reg));
 }
 
 static unsigned int regmap_mmio_ioread32be(struct regmap_mmio_context *ctx,